This unknown black brown mineral is strange, I really do not understand, behind the details of the picture to see it, it and calcite and green fluorite symbiotic, just a few pieces, like not to miss.

Our Mineral crystal Shop at Shantou,Guangdong,China
We can offer all kinds of chinese mineral crystals by wholesale or by retail.You are welcome to contact us in free time!
When in China, please come by for a visit. I would be very happy to meet with you!